Means for regulating the speed of knitting machines



1934- K. R. LIEBERKNECHT 1,977,729

MEANS FOR REGULATING THE SPEED OF KNITTING MACHINES Filed Sept. '7, 1932 2 Sheets-Sheet 1 M TORNEzj K. R. LIEBERKNECHT Oct. 23, 1934.

MEANS FOR REGULATING THE SPEED OF KNITTING MACHINES Filed Sept. '7, 1932 2 Sheets-Sheet 2 1 v lviubilll &

BY A I? m [N ATroRN \Q) Patented Oct. 23, 1934 UNITED STATES PATENT OFFICE MEANS FOR REGULATING THE SPEED OF KNITTING MACHINES Application September '7, 1932, Serial No. 631,989 In Germany March 19, 1932 This invention relates to the provision of a variable speed drive for knitting machines and, in particular, flat' full fashioned hosiery machines in which the variations in speed may be controlled mechanically or manually, or both mechanically and manually if desired, and in which the speed may be infinitely varied over the entire range of which the drive is capable.

In the use 01 flat knitting machines for the manufacture of certain fabrics, full fashioned hosiery for example, it is necessary to vary the speed during the knitting of difierent parts, for instance for the knitting of the leg the machine should be run at a higher speed than during the knitting of the welt, whereas the high heel and heel portions should be knitted at a lower speed than the welt portion. Also when iashioned fabric is concerned the speed of the machine must be reduced during the narrowing operation.

At certain times when adjustments are being made, or the machine is being set to begin certain work, it is necessary that it be turned very slowly indeed, say at one-tenth the normal speed. This is usually done by hand or by an auxiliary motor through special gearing.

Knitting machines used to be driven from a line shaft having a belt and pulley. arrangement whereby a high and'low speed could be obtained.

Variations in speed of the modern knitting machine are usually accomplished either by the use of multi-speed motors of the pole changing type which provide for two fixed speeds, or by the use of variable speed slip ring type motors in combination with field or armature resistance control, or by a brush shifting motor.

The above mentioned types of motors while effective in controlling the variations of speed, also present objectionable features. For instance, in the multi-speed motor of the pole changing type. because its speeds are fixed, it is impossible to vary the ratio of its speeds which at certain times is necessary in changing from one style of hosiery to another.

In some cases slip rings are provided on multi-speed motors to give a much more flexible range of speed but when thus used they are open to the same objection as variable speed motors and are more costly in their control. 7

In using variable speed motors there is provided a flexibility in speed range but speed regulation is effected by introducing more or less 5 Claims. (01. 68-82) tors as electrical energy is used to slow down v the speed, and such energy is not performing useful work but manifesting itself in heating up the motor and control equipment. Also the speed of this type of motor is determined by the 0 load on the machine and since this changes at certain periods of the knitting the speed is not uniform. Furthermore the starting torque is not what it should be in such a motor, particularly when the machine is heaviest loaded, as 65 when knitting the heel, where, because of the throttled speed due to the load, it has less torque than at high speed when the load is lighter.

In none of the prior types of motor above referred to is it possible to secure a practical speed 70 variation ranging between the highest running speed and the low speed necessary when adjustments are to be made or to set the machine accurately to begin certain operations, so that this low speed has been obtained by turning the machine by hand or by the use of an auxiliary motor as above described.

The object of the present invention is to provide a mechanical speed regulator between a constant speed power source (such as a simple so constant speed electrical motor or line shaft), and the machine to be driven, which possesses the inherent advantages of the type of drives described but none of their disadvantages. It consists of interposing' between such power source and the machine a hydraulic transmission element capable of infinitely varying the speed, between certain desired ranges, of the driven machine, and controlling this hydraulic element either manually or' mechanically from the driven machine.

The hydraulic transmission unit consists basically of an oil pump and hydraulic motor contained in a common housing. Both or either the oil pump or hydraulic motor may be regulated. The regulation of oil pump changes the power delivered and speed, torque remaining constant, while regulation of the hydraulic motor does not afiect the power delivered .but

changes the torque and speed.

The invention employs the manually operated starting rod of machine to control the hydraulic motor while the mechanically operated narrow- .ing patternor narrowing chain controls the oil pump. Since, when narrowing, less power is rem5 quired than when knitting, the power and speed are automatically reduced through control of the oil pump from the narrowing chain, while in ordinary knitting the power remains the same, n

changes in speed and torque being effected by regulating the hydraulic motor from the manually operated starting rod.

The invention is further disclosed by the accompanying drawings, of which- Figure 1 is a schematic front elevation of the power unit, transmission, and controls;

Fig; 2 is a schematic elevation of the oil pump controls;

Fig. 3 is a schematic plan view of the oil pump controls;

Fig. 4 is a schematic longitudinal section of the hydraulic transmission; and

Fig. 5 is a section of one unit of the hydraulic transmission on the line A-A of Fig. 4.

Hydraulic transmission, generally indicated by the reference numeral 1, is not of itself a part of this invention. Transmissions of this type are well known and obtainable in the open market. Consequently this transmission is shown schematically with only such detail as is essential to the understanding of the invention. Transmissions of this type consist of two units, 2 and 3, substantially identical in character. Each unit consists of an eccentric rotary pump, one of which is driven from any source of power of constant speed, such as an electric motor 4. This pump unit 2 discharges into a similar unit 3, which I will call a motor unit, and causes it to operate, the power generated by the motor unit 3 being utilized to run the machine through a suitable drive. Both of units 2 and 3 are contained withinan outerhousing 5 provided with suitable bearings for two separate aligned shafts 9 and 10 and with an oil reservoir in its base.

' Upon shaft 9 is keyed a rotor 12 provided with lates specifically to a means of controlling the radial recesses 13 for the reception of vanes 14. Channels 15 also extend from the periphery of the rotor through its shaft bearing to connect with channels 16 and 17, as the case may be, in the shaft, these channels in turn connecting with channels in the shaft (not shown) to form the intake and exhaust passages.

Enclosing rotor 12 is a casing 29 mounted upon bearings in a yoke 21 so that it may rotate freely in the same general plane on the rotor 12. Yoke 21 is in turn carried by suitable bearings in housing 5 so that casing 20 may be moved horizontally in its plane of rotation so that its degree of eccentricity with respect to rotor 12 may be varied. Vanes 14 change the space 22 between rotor 12 and casing 20 into a number of oiltight compartments of varying capacity.

Motor unit 3 is exactly like pump unit 2 described above, the rotor being afllxed to its own shaft 10 which transmits the power developed by the motor unit 3 to the machine through suitable driving connections, and its casing being mounted on a similar sliding yoke whereby the eccentricity of the casing with respect to the rotor may be varied.

The manner in which such transmission operates is well known and requires no description beyond saying that both unitsare completely filled with oil and that pump 2, driven by motor 4 coupled to shaft 9, exhausts into motor unit 3 and thus drives it. The power output of unit 3 is fed to the machine to be driven by means to shaft 10, chain 25, and sprocket 26 on drive shaft 27 of the machine. All of the above is found in transmissions now on the market and forms no direct part of this invention which reoperation of a hydraulic transmission, of which this is one example, from and by the driven machine.

As already stated, the casing 20 of each of poses of illustration comprises a shaft 26 rotatably mounted in housing 5 and provided with a thread 27" which engages with yoke 21. Shaft 26 projects from housing 5 and to its external end is aflixed a crank 29, in the case of the oil pump unit 2, and a. sprocket 30 in the case of the motor unit 3. By turning crank 29 the pump unit is controlled, and by turning sprocket 30 the motor unit is controlled; the control in each case being the adjustment of the eccentricity! of the pump casing, in one case, and. the motor casing in the other with respect to their particular rotors.

"Control lever 29 may be operated by the following means. To thefree end thereof is connected one end of a rod 31, the other end of -which is attached to one arm 32 of a bell crank supported by a pivot 33 on the knitting machine. The other arm 34 of the bell crank is provided with a pin 35 extending above and transversely of a pattern chain 36, which may be the narrowing pattern chain of the machine. Between pin 35 and pattern chain 36 is a. rocker arm 3'7 provided with a riser or cam 38 adapted to be engaged by the buttons 39' of oneseries of buttons on the pattern chain 36. These may be the buttons which operate the narrowing mechanism. A spring 40 serves to maintain contact between pin 35 of rocker arm 37 and to normally depress the rocker arm 37. Control lever39 is consequently normally held in position E, at which the maximum eccentricity between the casing and rotor of the pump unit 2 exists. This, of course, is the-position of highest speed for the pump.

4 When a button 39 passes under cam 38 rocker arm 37 and bell crank arm 34 are raised and consequently control lever 29 is swung to the left to the position M, the slow running position, such as would be required for example during the narrowing operation. As soon as button 39 leaves cam 38 lever 29 is again shifted to high speed position E and the machine assumes its normal knitting speed.

To automatically stop the oil pump unit a second rocker arm 41 is provided upon the machine, the free endtof which also engages with the underside of pin 35 and which is provided with a cam 42 corresponding in height with cam 38 on rocker arm 3'7 and also an additional cam 43, which is higher. These cams engage buttons 44 of a second series of buttons on pattern chain 36. When button 44 passes under cam 42 arm 41 is raised sufficiently to cause control lever 29 to be swung from the normal speed positionE to slow speed position M. When button '44 passes from cam 42 to higher cam 43 rocker M41 is raised still higher and control lever 29 is moved still further to the left to full stop position A, at which the pump rotor unit 3, although electric motor 4 continues to run at normal speed.

The motor unit 3 may be controlledmanually by means of mechanism operated by the start- 6 ing rod 45 of the knitting machine as shown in Fig. 1. As is well known, the starting rod is simply a longitudinally shiftable rod conveniently mounted upon the machine. The starting rod 45, as shown in Fig. 1, is provided with a rack 46 which meshes with a sprocket 47 to rotate the sprocket when the rod is pushed one way or the other. Sprocket 47 is connected to motor control sprocket 30 by a chain 49. By this means the sliding yoke of motor unit 3, may be operated to control the output of the motor unit in the same manner as already described for the oil pump.

I also provide means for stopping the electric motor 4 substantially concurrently with the stopping of the power :utput of motor unit 3. This consists of a switch 50 in the motor circuit, the operating arm 51 of which is connected to rod 52 to one arm of a bell crank 53, the other arm of' which is adapted to engage with a stud 54onthestartingrod45sothatwhenthe starting rod is shifted from the position shown in Pig. 1 to its extreme left position (during which the motor unit will have been slowed down) contact with bell crank 53 to cause it to the switch into open circuit position and to hold it there until the starting rod is the right, whereupon switch 50 will again be closed through the action of spring would otherwise exist between the casings and the rotor vanes, since the movement of the casings with respect to the rotors is substantially reciprocatory instead of eccentrically rotative. The rate of discharge ofeach unit is determined simply by the eccentricity of its;

,rotor with respect to its casing. The greater the eccentricity the greater the discharge from each. Thegreaterthedischargefromthepump the greater the power which will be supplied to turn the hydraulic motor. By sulating the pump alone the speed of the hydraulic motor may be varied. However, since the working characteristics of .the motor have not been changed its turning eflort or torque remains constant. By regulating the eccentricity of the motorunitpartainsteadofthoseoftheoil pump, the power delivered to the motor unit will be unvarying, but the speed of the motor will be increased, when the eccentricity of its parts is reduced, and reduced when the eccentricity of its parts is increased. Thu e characteristics obviously-produce extreme flexibility in control of operating speed and power.

I claim:

1. Means for controlling a hydraulic transmission unit in the power drive of a knitting machine which comprises a pattern chain provided with a multiplicity of longitudinally parallel rows of buttons, two rocker arms each adapted to engage with the buttons of diiierent rows, a bell crank, a pin in the end of one arm of said bell crank extending over and pressing upon all of said rocker arms, an operating connection between the other arm of said bell crank and the hydraulic transmission speed control whereby the speed of the hydraulic transmission is automatically controlled by the pattern chain.

2. In a full fashioned knitting machine, a constant speed power source, a hydraulic transmission unit coupled thereto and comprising an oil pump and a hydraulic motor, said oil pump being driven by said constant speed power source so as to'operate the same to provide power to operate the hydraulic motor, means for transmitting the power output of said motor to the driving shaft of the machine, means operated by a pattern chain of the knitting machine, for automatically controlling the power output characteristics of the oil pump, and means operated by the starting rod of the knitting machine for controlling the power output of the hydraulic motor.

. draulic motor, said oil pump being driven by said constant speed power source to enable it to provide power for operating the hydraulic motor,

means for transmitting the power output of said motor to the driving shaft of the machine, means operated by a pattern chain of the machine for automatically varying the output characteristics of the oil pump, and means operated by the starting rod of the knitting machine for varying the power output of the hydraulic motor, and means operated by the said starting rod for stopping the electric motor concurrently with the stopping of the power output of said hydraulic motor.

4. In a full fashioned knitting machine, a constant speed power source comprising an electric motor, a inrdraulic transmission unit coupled thereto and provided with an oil pump and a hydraulic motor, said oil pump being constantly driven by said electric motor so that it will supply power to operate said hydraulic motor, means associated with. said hydraulic motor to transmit the power generated thereby to the drive shaft of the machine, means operated by the pattern chain of the machine to vary the power delivered to the hydraulic motor by the oil pump without effecting the operation of the electric motor, and means operated by the starting rod of the knitting machine to vary the power delivered by the hydraulic motor.

5; In a full fashioned knitting machine, a constant. speed power source comprising an electric motor, a hydraulic transmission coupled thereto and provided with an oil pump unit and a hydraulic motor, the operations of said oil pump unit being automatically regulated from the narrowing chain of the knitting machine and the operations of the hydraulic motor being regulated from the manually operated starting rod of the machine. v 

